Biomass burning is the burning of living and dead vegetation. It
includes the human-initiated burning of vegetation for land clearing and
land-use change as well as natural, lightning-induced fires. Scientists
estimate that humans are responsible for about 90% of biomass burning
with only a small percentage of natural fires contributing to the total
amount of vegetation burned.

Burning vegetation releases large amounts of particulates (solid
carbon combustion particles) and gases, including greenhouse gases that
help warm the Earth. Greenhouse gases may lead to an increased warming
of the Earth or human-initiated global climate change. Studies suggest
that biomass burning has increased on a global scale over the last 100
years, and computer calculations indicate that a hotter Earth resulting
from global warming will lead to more frequent and larger fires. Biomass
burning particulates impact climate and can also affect human health
when they are inhaled, causing respiratory problems.

Ground-level view of burning savanna
grasslands in South Africa. Greenhouse gas
carbon dioxide and solid carbon soot particulates
are components of the emissions. When inhaled,
the particulates lead to respiratory problems.

Since fires produce carbon dioxide, a major greenhouse gas, biomass
burning emissions significantly influence the Earth's atmosphere and
climate. Biomass burning has both short- and long-term impacts on the
environment. Vegetation acts as a sinka natural storage areafor carbon
dioxide by storing it over time through the process of photosynthesis.
As burning occurs, it can release hundreds of years worth of stored
carbon dioxide into the atmosphere in a matter of hours. Burning also
will permanently destroy an important sink for carbon dioxide if the
vegetation is not replaced.

What is the annual, global amount of greenhouse gases that are
released into the atmosphere due to biomass burning? How does biomass
burning impact the Earth's atmosphere and climate? Researchers involved
in the Biomass Burning Program at NASA Langley Research Center (LaRC)
are currently working to answer these questions. The major goal of this
research is to quantify the effects of global fires on the composition
and chemistry of the atmosphere and the Earth's climate.

Field ExperimentsFrom 1986-1993, LaRC scientists conducted 12 field experiments from
aircraft to measure the amount of gases and particulates from fires in
six different ecosystems. Measurements were taken during chaparral fires
in California (1986, 87), wetland fires in Florida (1987, 88), boreal
forest fires in Canada (1987, 88, 89, 90), tropical rainforest fires in
Mexico (1990, 91), savanna grassland fires in South Africa (1992), and
boreal forest fires in Siberia (1993).

Scientists also studied the southeast Asia fires in 1997. These
fires were unique since they involved both the burning of above-ground
vegetation and below-ground peata form of coal. Smoldering peat
produces more gases and particulates than burning vegetation per unit
area. These fires covered an area of more than 45,000 square
kilometersan area comparable to the combined area of Rhode Island,
Delaware, Connecticut, and New Jersey. The fire's thick smog cloud
covered almost all of southeastern Asia, resulting in more than 20
million cases of smog-related health problems. Gases and particulates
produced during the 1997 fires were measured as far away as Hawaii.

From these field experiments, scientists measured greenhouse gases
(carbon dioxide, methane, and nitrous oxide), chemically active gases
(carbon monoxide and nitric oxide), and particulates from diverse
ecosystems. This research showed how the production of gases and
particulates from fires varies with the type of ecosystem burned, the
fire's characteristics, and the vegetation's moisture content. As a
result of these measurements, LaRC researchers developed a fire
combustion model to determine emissions from each ecosystem based on
fire temperature. Knowing the amount of emissions is important for
accurate estimates of the environmental impacts of these greenhouse
gases. In addition, this model is useful for determining the
contribution of biomass burning to the total production of green-house
gases, a requirement for the Kyoto Treaty. This international treaty
limits the amount of greenhouse gas emissions of certain industrialized
nations.

Researchers also discovered that bacteria in soil enhance production
of the greenhouse gas nitrous oxide. Nitrification is a biological
process where bacteria convert ammonium, found naturally in soil and
also in fire ash, to nitric oxide and nitrous oxide. They believe that
the increased concentrations of ammonium in the ash lead to more
nitrification after a fire, thereby releasing additional nitric oxide
and nitrous oxide. The amount of these gases produced by bacteria after
a fire may surpass the amount released during biomass burning.

Space MeasurementsBurning
of savanna grasslands in Mozambique
in southern Africa as photographed by
astronauts aboard the Space Shuttle. The fire
plumes containing particulates and gases travel
thousands of kilometers from their origin. Vegetation appears
red in the false-color photograph.

The only way to accurately determine the exact location and extent
of fires is to have a global perspective from space, making space-based
measurements extremely important. Since no satellite has ever been
dedicated to fire monitoring and measuring, most observations of fires
from space are obtained from existing satellites developed for other
purposes. Astronauts also photograph fires from the Space Shuttle (Fig.
2). Fire measurements come from the Defense Meteorological Satellite
Program (DMSP) satel-lites and the Advanced Very High Resolution
Radiometer (AVHRR) on the National Oceanic and Atmospheric
Administration (NOAA) satellites. DMSP nighttime images provide
information about the location and frequency of active fires, while
AVHRR satellites can help determine the size of the area burned. Remote
sensing of global fires indicates that Africa is the "fire center" of
the planet with more biomass consumed by fire in Africa than anywhere
else on Earth.

Africa is the fire center of our planet with
more biomass burned on an annual basis than
anywhere else. The upper image of the two above shows the
global distribution of fires, represented by red orange, and yellow dots (lighter colors indicate more fires),
while the lower of the two images shows the fire distribution in Africa. They are both based on nighttime
measurements obtained by the DMSP Operational Linescan System.

Future ResearchThe year 2000 was one of the worst fire years ever recorded in the
United States. As of November 14, 2000, a total of 90,674 wildfires
burned 7.26 million acres across the United States as compared to the
previous ten-year average (1990-1999) of 3.79 million acres burned. On
one day, August 29, 2000, 84 large fires (100 acres or more) were
burning simultaneously. Total fire suppression cost in 2000 was about
$1.6 billion, making fire monitoring an important social, health,
economic, and national security concern.

Igniting the controlled fire at the base of the Impact Dynamics
Research Facility at LaRC on January 31, 2001. This facility, previously
named the Lunar Landing Research Facility, was originally used by the
Apollo astronauts to practice lunar landings.

Scientists are continuing to develop new instruments for measuring
and monitoring fire from aircraft and spacecraft. This research will
help assess the impact of fire-produced gases and particulates on
atmospheric composition and chemistry and on climate. In August 2000 and
January 2001, researchers set controlled fires at the Impact Dynamics
Research Facility at LaRC to test new fire monitoring and measurement
instrumentation that will eventually help researchers study global fires
(Fig. 4 and Fig. 5). Tests like these will support the Interagency
Agreement signed in November 2000 between LaRC and the United States
Department of Agriculture Forest Service.

About 165 feet above the controlled fire in the gantry of the Impact
Dynamics Research Facility, visible and infrared fire monitoring instruments,
at bottom right, record the fire temperature, the rate of fire spread, and the
area burned. These instruments are being readied for flights over wildfires
on United States Forest Service airplanes.

In this partnership, LaRC will develop instruments for the remote
sensing of fires to be flown on aircraft by the Forest Service.
Instruments will monitor active fires, measure fire temperature and the
area burned, and provide an exact geographical location of a fire.
Information from these instruments will also help fire fighters more
efficiently and economically plan how to control and fight fires. The
fire monitoring instrumentation will provide information about the fire
to the ground in real time, giving fire fighters an unique and
comprehensive perspective to help meet the growing demands of fire
control in the United States.